Most of the earlier FGW liveries don't sell for particularly high amounts. The one exception to this is HSTs in fag-packet livery, which sell on ebay for a fair amount (although not anywhere near as high as the current-livery Hornby models). I understand that these are rare because only Lima ever produced them, and they went bust part-way through the production so not many were actually made. After Hornby had acquired the Lima toolings, they made a TGS (only) in this livery, which they said was due to customer demand. I really cannot see how this can be possible (they were available new for ages, so clearly not high demand!) - it seems much more likely that what people actually wanted was a Merlin livery TGS to go with their Hornby Merlin-livery HSTs (which had the scale-length coaches, but at the time they were made Hornby didn't have tooling for a TGS) and Hornby somehow misunderstood.
I did wonder whether Hornby would produce fag-packet livery this year, but they have gone for the original MML livery instead - a rather strange choice as both Lima and Hornby have previously produced it, and the the models of the current EMT livery didn't appear to sell particularly well - they were discounted at a number of sellers for quite a while. I guess this is because the MML is more or less a single route, and a relatively short one, so there was much less demand than for the FGW sets, plus of course the HST fleet is much smaller than that of FGW.